The difference is that MyBatis is different from other methods

The difference between MyBatis and other writing methods requires specific code examples

With the continuous evolution of Java development, more and more ORM (Object Relational Mapping) frameworks have appeared in the developer’s perspective. Among them, MyBatis, as a classic ORM framework, is loved by the majority of developers. Compared with other writing methods, MyBatis has some significant differences. These differences will be explained below through specific code examples.

1. Decoupling of persistence layer code and SQL
   In traditional JDBC programming, we need to write a large number of SQL statements in the code to interact directly with the database. MyBatis decouples SQL statements from Java code by configuring XML mapping files, so that we only need to focus on business logic without having to care about specific SQL statements. The example is as follows:

// 使用MyBatis之前
public User getUserById(int id) {
    Connection connection = getConnection();
    String sql = "SELECT * FROM user WHERE id = ?";
    PreparedStatement preparedStatement = connection.prepareStatement(sql);
    preparedStatement.setInt(1, id);
    ResultSet resultSet = preparedStatement.executeQuery();
    // 处理结果集
    // ...
}

// 使用MyBatis之后
public User getUserById(int id) {
    return sqlSession.selectOne("UserMapper.getUserById", id);
}

Through the above code example, we can clearly see that after using MyBatis, we only need to call the sqlSession method to transfer the specific SQL statement The execution process is handed over to the MyBatis framework.

2. Flexibility of parameter passing
   In traditional JDBC programming, we need to pass parameters in the form of question mark placeholders, which is very cumbersome. MyBatis allows us to pass parameters through the #{} tag, and also supports various complex types of parameter passing. An example is as follows:

// 使用MyBatis之前
public List<User> getUsersByCondition(String name, int age) {
    Connection connection = getConnection();
    String sql = "SELECT * FROM user WHERE name = ? AND age = ?";
    PreparedStatement preparedStatement = connection.prepareStatement(sql);
    preparedStatement.setString(1, name);
    preparedStatement.setInt(2, age);
    ResultSet resultSet = preparedStatement.executeQuery();
    // 处理结果集
    // ...
}

// 使用MyBatis之后
public List<User> getUsersByCondition(@Param("name") String name, @Param("age") int age) {
    Map<String, Object> paramMap = new HashMap<>();
    paramMap.put("name", name);
    paramMap.put("age", age);
    return sqlSession.selectList("UserMapper.getUsersByCondition", paramMap);
}

Through the above code example, we can see that after using MyBatis, we can pass parameters directly through the annotations of method parameters, without having to manually set the location and type of parameters.

3. Caching mechanism support
   MyBatis has a built-in powerful caching mechanism that can greatly improve the efficiency of data query. Under the same query conditions, MyBatis will first obtain the data from the cache. If it does not exist in the cache, it will execute the SQL query and store the data in the cache. The example is as follows:

// 使用MyBatis之前
public User getUserById(int id) {
    Connection connection = getConnection();
    String sql = "SELECT * FROM user WHERE id = ?";
    PreparedStatement preparedStatement = connection.prepareStatement(sql);
    preparedStatement.setInt(1, id);
    ResultSet resultSet = preparedStatement.executeQuery();
    // 处理结果集
    // ...
}

// 使用MyBatis之后
// 注解配置缓存
@CacheNamespace(size = 1024)
public interface UserMapper {
    @Select("SELECT * FROM user WHERE id = #{id}")
    @Options(useCache = true)
    User getUserById(int id);
}

Through the above code example, we can see that after using MyBatis, we only need to use the @CacheNamespace annotation to configure the cache, and @ OptionsSet useCache = true in the annotation to enable the cache function.

Summary:
The above are specific code examples of some differences and advantages between MyBatis and other writing methods. Compared with traditional JDBC programming, MyBatis provides a more concise and readable way of writing code by decoupling SQL and Java code. At the same time, MyBatis also supports the flexibility of parameter passing and a built-in caching mechanism, which can greatly improve development efficiency and system performance. Therefore, in actual development, we can choose to use MyBatis as the ORM framework to better organize and manage database operations.

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